A - 34 A Suspected Case of Early-Onset Frontal Variant of Alzheimer's Disease in a 64-Year-Old Male.

OBJECTIVE: Early-onset frontal variant of Alzheimer's disease (fvAD) is characterized by apathy, disinhibition, and executive dysfunction. As such, fvAD is often difficult to clinically distinguish from behavioral variant frontotemporal dementia (bvFTD). However, research suggests that a differentiating feature among the two conditions is that fvAD typically presents with more pronounced memory impairment. Therefore, neuropsychological testing in the context of a comprehensive multidisciplinary assessment can be a valuable tool to aid with differential diagnosis.

METHOD: A 64-year-old male with gradually progressive difficulties in cognition and behavioral-emotional functioning over the past 8-9 years presented to a multidisciplinary neurology clinic. MRI showed mild atrophy in the frontal, temporal, and parietal lobe regions. Concerns were raised by his neurologist for early-onset ad versus bvFTD so the patient was referred for neuropsychological evaluation.

RESULTS: Neuropsychological testing showed a largely amnestic memory profile along with deficits in executive functioning and semantic fluency. His spouse endorsed concerns for apathy and executive dysfunction on a frontal system rating questionnaire in addition to concerns for disinhibition during the clinical interview. Taken together, the patient's profile appeared to be consistent with early-onset fvAD. Follow-up FDG-PET scan showed decreased uptake in the anteromesial temporal lobes, posterior cingulate cortices, and posterior temporoparietal regions which was consistent with an ad profile.

CONCLUSIONS: Early-onset fvAD and bvFTD are often difficult to clinically distinguish from each other. However, neuropsychological testing in conjunction with comprehensive multidisciplinary assessment can serve an important role in helping to facilitate differential diagnosis for these two neurodegenerative disorders with overlapping features.